rotate option of pango producer seems not working about mlt

[bmatherly]

following shell will produce non-rotated text rendering in the video.

Rotated text is not supported when the pixel aspect ratio is not 1.0.

You can work around this by specifying a profile with square pixels.

For example, try this:
melt -profile atsc_720p_30 color:red out=250 -track -producer pango rotate=-90 text="Hello2" out=250 -transition composite

Result:

Your comments about the gravity are true, but not a bug. Just not implemented. We would welcome a patch to improve it. Also, just so you know, the pango producer is pretty old and has fallen out of favor for the qtext producer. I don't think that producer will support your rotation needs either. But if you are thinking about submitting code improvements, you might want to focus on qtext instead of pango.

[myme5261314]

Thanks for your help. It's good to know the rotate option of pango producer works with square pixel only.

I assume pango project still have some activities (https://gitlab.gnome.org/GNOME/pango/) and had already implemented the vertical text many years ago. (https://mces.blogspot.com/2007/05/advanced-opentype-features-in-pango.html)

Actually I can't find a proper way to implement vertical orientation text via qtext.
Even though qtext seems to support subset of html tags (https://doc.qt.io/qt-6/richtext-html-subset.html), but the most relevant feature lies in not included css property (https://developer.mozilla.org/en-US/docs/Web/CSS/text-orientation).